Switch cleaning device



a 1932 e. l INTON ET AL 1,340,116

SWITCH CLEANING DEVICE Filed 001:. 7, 1926 3 Sheets-Sheet l Jan. 5, 1932.

cs. 'LINTON ET AL SWITCH CLEANING DEVICE Filed 005:. 7, 1926 3 Sheets-Sheet 2 /nvenf0r.s: 6mm Lmfm v Ja/m A Ermsend Jan. 5, 1932. e. LINTON ET AL SWITCH CLEANING 'DEVICE Filed Oct. 7,' 1926 3 Sheets-Sheet 3 H 9% wmw m m VET Mmn r fl Patented Jam 5, 1932 .y iTEDTfSTATESrAT-ENt OFFICE- 1 GRANT LIN'ro OF NEW YORK, N. Y., A D JoH- -n. rowN's NnoE BLOOMFIELID, NEW

JERSEY, AssIGNoRs'ro BELL TELEPHONE LABORATORIES, rNconron-A'rEn, or NEW YORK, N. Y., A'ooRPoRArIo or NEW YORK I it swrrcn' 'ctEANINe DEV CE Application filed October 7, 1926. scrim No. 140,d46.

Thisv invention relates to cleaning devices employing air currents and more particularly. to devices of this type for clean ng switches. 1 The object of this invention is to attain effective cleaning of selector switch terminal banks by currents of air drawn through the banks by any suitable suction apparatus whereby the dust which may havecollected on the terminals. ofthebank may be :dislodged and collected in a suitable container or otherwise disposed of in a-manner to prevent it from settling on surroundingobjects. A device for cleaning swltches constructed in accordance with this inventionmay for example, in the case of rotary switches 1 having semi-circular" terminal banks,:, consist of plates or cowling members attachable to the ends of a terminal bankto form with the switch structure an air passage past the ter- 1 minals ofsaid bank. This arrangementmay be used in combination with conventional dust collecting apparatus so applied to one end of said air passage that thedust particles 1 showsin 'perspectivethe preferred form of the vacuum cleaning attachment in accordance with the invention; Fig. 2 shows a simplified form of suction nozzle. Figs. 3 and 4' illustrate the preferred vform as applied to a rotary switch of the type commonly usedfin automatic telephoneofiices. Fig is a perspective view of such a switch with a structure "in accordance .with this invention 'applied thereto, while Fig. dis a Ypartiallon'gi 4; It shouldbe understood in. connection;

tudinal cross-section of, the arrangement shown in Fig. 3. Fig.5 shows the modified form of nozzle shown Fig. 2 applied to the, same type of switch, 'Fig. 6'shows another" modification of the inventionsimilar to that shown in Fig, 5.

" Reference may now be had to Figs. .1, 3 and withthese two figuresthat although rotation switch structure.

-with the stepping magnet structure 9 and the of the brushes is not contemplated as a necessary part of the cleaning operation, it is desirable to provide an arrangement that can past the terminals 2 of the semi-circular switch bank 3 of thisswitch l and yet not interfere with the normal functions of the switch and particularly its brushes 4, a-semis cylindrical box-shaped cover orcasing 5 is provided which'is so shapedthat it can be readily placed over the open side of the I The semi-circular end plates 6 of the cover or casing 5 are'fitted over the'end pieces of the frame 7 of the switch.

This switch frame .7 serves, as is evident from the drawings, as a mounting for the switch .bank' and stepping magnet and as bearings for the shaft on whichthe brushes 4 and the usual ratchet'whe'el 8 driven by the stepping magnet 19 are 1nounted.- The cover is pro-.

stepping magnet9- and a plate 15 of insulating material is attached to the side wall-6 to complete the closure of theside wall. The side wall is constructed of insulating material atthis point to guard against having; this side "of the cover come into electrical contact spring contact arrangement 14.. A clearance is also made inthis side plate 6 and'its insula tedlportion 15 at 16 for a-stop screw .em-

ployedito adjust the pawl 13 In the particular 'arrangementof Figs-l, 3 and 4 the ends of th'eterminal bank'itself are covered by. semi-circular. plates such. as

18, one on each'end e f-the bank. These plates may consist of an inner semi-circular portion 19 ofmetal and an outer portion or gasket 20 of a flexible material such as. rubber-sheet.

End plates constructed in this manner serve to provide a substantially air-tight cover for the ends of the terminal bank, as will hereinafter be described. In the arrangement shown, the plates 18 are connected respectively at 22 to handles 23 pivoted together at 24 and normally held by a spring 25 so as to press the plates 18 closely against the ends of the terminal bank. The handle 23 incidentally serves to secure the cover 5 in place by being fitted into recessed portions 26 in the plates 6 and having lugs 27 registering with holes (not shown) in the recessed portions 26 and by being bent inwardly near the ends 22 over the switch frame7.

To prepare for the cleaning of a switch by means of the device hereinbefore described, the cover 5 is first placed in position to enclose the open front side of the switch bank and then the outer ends of the handles 23 carrying the side plates 18 are pressed to separate the plates to such an extent that they may be passed overthe side walls 6 of the cover. The handles 23 are then released, thereby permitting the plates 18 to tightly engage the sides of the terminal bank with the u 27 registering with the corresponding ho es in the plates 6. Suction is then applied from a suction dust collecting device which may be connected by means of an air hose to the suction nozzle 11. Experimentation has shown that with this structure the main body of the air stream created by the suction apparatus will pass through the inlet duct 10 around the shaft holding the brushes 4 over the terminals 2 and out through the nozzle 11, as indicated by the arrows. This path is followed rather than the shorter path from the inlet duct 10 directly to the nozzle 11, by virtue of the shape and positioning of'the duct 10 with relation to the terminals as shown in Fig. 4 and the momentum acquired by the air during its passage through this inlet duct. It should be noted that, with the correct relation between the strength of the air stream and the flexibility of the gaskets 20, the latter will be drawn tightly against the sides of the terminal bank to create a substantially air tight passage around. the bank. This, coupled with the fact that the air stream is directed along the path indicated, causes the removal of dust particles from the portions of the switch forming part of the enclosing wall of the passage, to wit, terminals, brushes and the ratchet mechanism.

Referring now to the modified form of the invention as represented by Fig. 5, semi-circular plates 30 are shown permanently secured to the sides of the terminal bank 1 by means of screws such as 31. a

A further modification of the invention, as represented in Fig. 6, is similar to that shown in Fig. 5, except that the end plates in this case are so constructed as to be easily inserted on switches already in position on frames. As shown, semi-circular plates 40 fit snugly against the sides of the terminal bank and each is provided with two fiat springs and 46 that rest under tension with their free ends against the insides of the supporting frame 7 to hold the plates in place. A raised portion, such as 47, on the inner side of each plate is provided to locate the lates correctly and to prevent them from shi ting from the roper position.

In the two modifications of the invention represented in Figs. 5 and 6 cleaning can be conducted in conJunction with the use of a built-up cover member incorporating an inlet duct and an outlet nozzle substantially similar to cover 5 of Figs. 3 and 4, but the need of using the special temporary cowling arrangement constituted by the parts 18, 19, 20, 22, 23, 24, 25, and 27 of Figs. 1, 3 and 4 is obviated. The general method of cleaning described may therefore be considerably facilitated by the use of the permanent cowls of Figs. 5 and 6.

It should be noted in connection with the modification shown in Figs. 5 and 6, that if the switches are. of a type such that the brushes do not rotate beyond the front of the switch frame or have been made artificially busy so that the brushes cannot rotate beyond the front of the bank, cleaning may be conducted by using a simple form of nozzle such as 34, represented in Figs. 2 and 5. When using nozzle 34, the air passage is formed merely by the side plates and the inner surface of the bank 1 and the tips of the terminals 4 projecting therefrom, and the passage may therefore be considered as beginning at the point 32 and ending at the point 33. When the nozzle 34 is used with a switch made busy, and in which the brushes may occupy any position when made busy, the nozzle 34 may be placedeither at 32 or at 33 dependent on the articular position in which the brushes are ound.

The nozzle 34 is attached to the usual suction hose of a suction dust collecting a paratus and may be so shaped as to fit snug y in the opening at 33 or 32. It may be shaped as shown to prevent it coming into contact with the stepping magnet structure 9 and to pull the airfrom the bottom of the terminal bank in order to direct the air current around the terminal side of the bank.

It should be noted that the use of the permanent cowling members such as 30 or 40 at the ends of a switch bank may to some extent prevent the accumulation of. dust in the switches.

It is to be understood that this inventionis not limited in its application to the above mentioned type of switches but it is capable of being applied to switches of other'types or other apparatus in which the portions thereof desired to be cleaned are capablejof tact terminals, said attachment comprising a passage suction nozzle and means cooperating with the open end-and sides of the arcuate bank, for directing a current of air into said nozzle in an arcuate direction over the terminals of the bank. v

2. A suction cleaning attachment for a selector switch having an arcuate bank of contact terminals,said attachment having a suction nozzle, and detachable closure plates for the sides, of the bank forming with the inner arcuate face of the bank a,semicylindrical chamber for directing a current of air into said nozzle inan arcuate direction over the terminals of the bank. i

3. A suction cleaning attachment for an object to be cleaned having a substantially semi-cylindrical interior chamber normally open except along its cylindrical surface, and

closure plates for the sides of said chamber, said attachment having a suction nozzle for, engagement with a portion of the remaining open end of said chamber said closure plates and nozzle cooperating to direct a current of air in said chamber in an arcuate direction over the cylindrical surface thereof.

4. A suction cleaning attachment for a selector switch having an arcuate bank of cone, tact terminals, andbrushes, said attachment comprising a semi-cylindrical casing for en'- gagement with the open end of thearcuate bank and having an inlet duct and a suction nozzle, and closure'plates for the sides of the bank said casing and closure plates forming V with the inner arcuate face of the bank a chamber for directing a current ofair in an arcuatedirection over the terminals of the bank. 5. A suction cleaning attachment for a selector switch having an arcuate bank of contact terminals and brushes, said attachment comprising a semi-cylindrical casing for en. gagement with the open end of the arcuate bank and having an inlet duct tangential to the upper portion of the cylindrical wall of said casing and a suction nozzle tangential to the lower portion of the cylindricalwall of said casing,and closure plates for the sides of the bank said casing and closure plates form ing with the inner arcuate faceof the bank a chamber for'directing a current ofair in an I arcuate direction over the-terminals of the of the bank,a handle. attached to each of said plates, said handles being pivoted together,

and a spring for pressing said plates firmly "against the sides of said bank when said plates have been by said handles.

7. A suction cleaning attachment for a selector switch having an 'arcua'te bank of contact terminals and brushes, said attachment positioned adjacent thereto comprising a semi-cylindrical casing for en- 7 gagement with the open end of the arcuate bank and having an inlet duct and a suction nozzle, detachable closure plates for the sides of the bank, spring'actuated pivoted handles attached to said plates for positioning saidplates against the sides of said bank and for holding them firmly in engagement therewith, and lugs" carried by said handles for engagement with the sides of said casing for holding said casing in position against the end of said bank.

8. .A suction cleaning attachment for a selector switch having an arcu-ate'bank of contact terminals, brushes, a brush shaft and a stepping magnet, said attachment compris-' ing asemi-cylindrical casing for engagement with the open end of the arcuate bank and having an inlet duct and a suction nozzle,

and detachable closure plates for the sides of the bank forming with the inner arcuate face of the bank and with the brush shaft a semi-toroidal chamber for directing a strong currentof air through said inlet duct over the terminals of said bank and through said nozzle,

In witness whereof, we hereunto subscribe our names this Gthday of October, A; D.,

' GRANT LINTON.

JOHN R. TOWNSEND." f

bank from said inlet duct into said nozzle.

6. A suction cleaning attachment for a selector switch having anlarcuate bank of contact terminals and brushes, said attachment Y comprising a semi-cylindrical casing for en'- 

